This disclosure relates to a rugged semiconductor radiation detector that can survive a high-temperature and/or high-vibration environment. The rugged semiconductor radiation detector may be used, for example, in well-logging in high-temperature, high-pressure borehole environments.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present techniques, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as an admission of any kind.
Identifying the composition of a geological formation can provide information about the likely presence or absence of hydrocarbons. As such, many downhole tools have been developed that attempt to analyze the geological formation from within a wellbore. These tools include, among other things, tools that emit ionizing or nuclear radiation into the formation and detect radiation that results using a radiation detector. The radiation that results may indicate the composition or other properties of the formation.
Some downhole tools, for example, may use a neutron generator to emit neutrons into the surrounding formation. The neutrons may interact with the elements that make up the formation in various ways depending on the composition of the formation. Different formation compositions may cause the neutrons to scatter in different ways. Thus, by detecting the manner in which the neutrons scatter in the formation and return to the tool, properties of the formation (e.g., density) may be estimated. The downhole tool may detect the neutrons using one or more neutron detectors at various spacings from the neutron generator. Moreover, many downhole tools may use a neutron monitor to accurately gauge the output of the neutron generator. Downhole tools may also measure other types of radiation using other radiation detectors, such as gamma-ray detectors, x-ray detectors, and so forth. The radiation detectors may use a scintillator (e.g., a plastic scintillator) that emits light when radiation interacts with the scintillator, and a photomultiplier to amplify the light signal.
Each of these radiation detectors takes up space in the downhole tool. This limits the number of radiation detectors that may be included in a downhole tool of a particular size. To include additional radiation detectors, the size of the downhole tool may be increased. However, increasing the size of the downhole tool may cause the downhole tool to become unsuitably large for certain applications. Some radiation detectors may take up less space (e.g., semiconductor detectors) by avoiding the use of photomultipliers, but these may be prone to degradation under harsh downhole conditions. Under these conditions, for example, the semiconductor detectors may suffer electrical failure due to arcing under high temperatures.